Ritchey-Common test of the large flatness is an effective method, which requires a larger aperture standard spherical
mirror. It’s very difficult for manufacture of large-aperture spherical mirror in the area of optical fabrication. The
producing technology of the large-aperture standard spherical mirror with aperture of 1.8m is mainly stated in this paper.
The solutions to solve the problems during manufacture are discussed, and the attentions during production are
concluded. To offset the gravity effect and ensure the surface deformation satisfy the design requirements, the mechanic
support structure including hammer and floating support of spherical mirror are illustrated in brief. At last, the analysis
and data of measurement given by 4D interferometer satisfy the technical indicators.